An LED (Light Emitting Diode) element, which is one of semiconductor light-emitting elements, is small in size, has a long life, and has an excellent power saving property. Therefore, it is widely used as a light source of an indicating lamp and the like. Further, in recent years, LED elements having higher luminance have come to be produced at relatively low cost and, accordingly, use of the LED element as a light source to replace fluorescent lamps and incandescent light bulbs is under consideration. When using the LED element as such a light source, in order to obtain large luminance, many of surface-mounted LED packages employ a method wherein LED elements are disposed on a substrate (LED-mounting substrate) comprising a conductive material, on which surface is formed a substance which reflects light such as silver and the like, and wherein a reflector (reflecting body) which reflects light to a prescribed direction is arranged around each LED element.
Incidentally, the semiconductor light-emitting element, such as the LED element used for a semiconductor light-emitting device, accompanies heat generation at the time of light emission and, therefore, there have been cases where the reflector deteriorates due to a temperature rise of the element, resulting in lowering of reflectance thereof, and a decrease in luminance of light emitted by the LED package.
Thus, heat resistance is required of the reflector and, therefore, a development of a reflector having improved heat resistance is progressing. For example, Patent Literature 1 proposes a thermosetting resin composition for light reflection, comprising (A) an epoxy resin, (B) a curing agent, (C) a curing catalyst, (D) inorganic filler, (E) a white pigment, and (F) a coupling agent.
Patent Literature 2 proposes a polyamide composition comprising a polyamide having dicarboxylic acid units containing 50 to 100 mole % of 1,4-cyclohexanedicarboxylic acid units and diamine units containing 50 to 100 mole % of C4-18 aliphatic diamine units.
Patent Literature 3 proposes a resin composition comprising (A) a fluorine resin having carbon-hydrogen bonds and (B) titanium oxide. Furthermore, Patent Literature 4 proposes even an electron beam-curable resin composition containing a specific cross-linking agent, and proposes a semiconductor light-emitting device in which the resin composition is used for the reflector.
Heretofore, as a method for mounting the semiconductor light-emitting device on a wiring substrate and the like, there has been employed a method (reflow method) where the semiconductor light-emitting device is temporarily fixed on the wiring substrate having solder applied beforehand in spots on predetermined places, and thereafter the semiconductor light-emitting device is fixed by using the solder melted by heating the wiring substrate generally to around 220 to 270° C. by means of infrared rays, hot air, and the like.
However, the semiconductor light-emitting devices which have conventionally been used are not necessarily sufficient in heat resistance, and particularly in the reflow process by heating, there are such problems that temperature of a component surface rises locally to cause a deformation; and the like. If the shape of the reflector changes, a reflection angle of light and the like also change, and thus it becomes difficult for the LED package to exhibit light-emitting characteristics as designed. Further, external dimensions of the LED package change to cause a defect in connection of the package to the wiring substrate. Therefore, there has been a desire for a semiconductor light-emitting device which is provided with a reflector having excellent dimensional stability to heat.